1. Field of the Invention
This invention relates to a height control linkage for a vehicle cab suspension and more particularly to a height control linkage for a vehicle cab suspension comprised of elongated lower and upper linkage members with the linkage members being able to be snapped together. Although the height control linkage is primarily designed to be used with cab suspension systems, it may also be used with vehicle chassis suspension systems.
2. Description of the Related Art
Many vehicle cab suspensions have been previously provided for supporting a vehicle cab on the chassis of the vehicle whereby a cushioning or shock absorber effect is achieved to provide a more comfortable ride for the occupant or occupants of the cab. Further, many vehicle cab suspensions have been previously provided for adjusting the height of the rear of the cab depending upon the weight of the occupants, etc., within the cab. For example, see U.S. Pat. No. 6,540,038 wherein a vehicle cab suspension system is disclosed including a pair of air bags or air springs which are positioned between the rear of the cab and the truck frame with the air bags being inflatably adjustable to exert an upward force against the underside of the cab. In the device of the '038 patent, the air pressure within the air springs therein may be adjusted through a displacement sensitive valve which is actuated by a selectively length adjustable rod arm. The rod arm or height control linkage of the '038 patent, and in similar prior art designs, requires that in the assembly of the rod arm or height control linkage, prior to installation, one linkage member must be screwed into the other linkage member with lock nuts then being tightened to maintain that length. If one of the linkage members is threadably moved with respect to another, the length of the rod arm changes. It is believed that the assembly of the rod arm of the '038 patent is time-consuming and ergonomically disadvantageous.
A generally similar device to that of the '038 patent is disclosed in U.S. Pat. No. 6,073,714 which includes a linkage arm which is connected to the leveler valve control arm. It is believed that the linkage of the '714 patent suffers the same drawbacks as that of the '038 structure.